Function findRelatedShapesRemove

mapcluster.c:456–497

traverse the quadtree to find the neighbouring shapes and update some data on the related shapes (when removing a feature) */

/* traverse the quadtree to find the neighbouring shapes and update some data 
on the related shapes (when removing a feature) */
static void findRelatedShapesRemove(msClusterLayerInfo* layerinfo, clusterTreeNode *node, clusterInfo* current)
{
    int i;
    clusterInfo* s; 
    
    /* -------------------------------------------------------------------- */
    /*      Does this node overlap the area of interest at all?  If not,    */
    /*      return without adding to the list at all.                       */
    /* -------------------------------------------------------------------- */
    if(!msRectOverlap(&node->rect, &current->bounds))
    return;

    /* Modify the feature count of the related shapes */
    s = node->shapes;
    while (s)
    {
        if (layerinfo->fnCompare(current, s))
        {
            if (s->numsiblings > 0)
            {
                /* calculating the average positions */
                s->avgx = (s->avgx * (s->numsiblings + 1) - current->x) / s->numsiblings;
                s->avgy = (s->avgy * (s->numsiblings + 1) - current->y) / s->numsiblings;
                /* calculating the variance */
                s->varx = (s->varx - (current->x - s->avgx) * (current->x - s->avgx) / s->numsiblings) * 
                                                    (s->numsiblings + 1) / s->numsiblings;
                s->vary = (s->vary - (current->y - s->avgy) * (current->y - s->avgy) / s->numsiblings) * 
                                                    (s->numsiblings + 1) / s->numsiblings;
                --s->numsiblings;
                ++s->numremoved;
            }
        }
        s = s->next;
    }

    /* Recurse to subnodes if they exist */
    for (i = 0; i < 4; i++)
    {
        if (node->subnode[i])
            findRelatedShapesRemove(layerinfo, node->subnode[i], current);
    }
}

/* setting the aggregated attributes */
static void InitShapeAttributes(layerObj* layer, clusterInfo* base)